Photoconductive materials that have conventionally been used for light-sensitive materials for use in electrophotographic processes include inorganic substances such as selenium, cadmium sulfide, zinc oxide, etc. However, they require difficult procedures for being made into light-sensitive materials which leads to high production costs, and, in addition, they have no flexibility and cannot be used in a belt configuration. Further, they are susceptible to heat and mechanical shock, so that much care is required in handling them.
In recent years, electrophotographic light-sensitive materials using various organic substances have been proposed in order to overcome the defects of the inorganic substances, and some of them have been put into practice. For example, such materials include an electrophotographic light-sensitive material comprising poly-N-vinylcarbazole and 2,4,7-trinitrofluoren-9-one (U.S. Pat. No. 3,484,237), an electrophotographic light-sensitive material wherein poly-N-vinylcarbazole is sensitized with a pyrylium salt type dye (Japanese Patent Publication No. 25658/73 corresponding to U.S. Pat. No. 3,617,268), a light-sensitive material primarily comprising an organic pigment (Japanese Patent Application (OPI) No. 37543/72 corresponding to U.S. Pat. No. 3,898,084 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application")), an electrophotographic light-sensitive material primarily comprising an eutectic crystal complex composed of a dye and a resin (Japanese Patent Application (OPI) No. 10785/72 corresponding to U.S. Pat. Nos. 3,732,180 and 3,684,502), etc.
These electrophotographic light-sensitive materials do not provide fully satisfactory sensitivity, though they do have higher flexibility and transparency than the light-sensitive materials of inorganic substances. Therefore, a highly sensitive electrophotographic light-sensitive material containing a pyrylium dye and a hydrazone compound has been proposed (Japanese Patent Application (OPI) No. 144833/83). However, this light-sensitive material is unsatisfactory in storage stability, and is further required to be improved with respect to light-sensitive wavelength region.